Quadric means: A surface whose equation in three variables is of the
second degree. Spheres, spheroids, ellipsoids, paraboloids,
hyperboloids, also cones and cylinders with circular bases, are
quadrics.

Zoospore means: A spore provided with one or more slender cilia, by the
vibration of which it swims in the water. Zoospores are produced by
many green, and by some olive-brown, algae. In certain species they are
divided into the larger macrozoospores and the smaller microzoospores.
Called also sporozoid, and swarmspore.